The present invention relates to a traversing yarn guide adapted for reciprocating an advancing yarn or the like to form a wound package on a yarn winding machine.
Conventional yarn winding machines include a yarn package mounting spindle, a drive for rotating the spindle and package, and an adjacent traversing system for traversing the yarn as it advances onto the package. The traversing system includes a drive roll having a cross spiraled groove, and an adjacent pair of guide rails having a slot therebetween which extends parallel to the axis of the drive roll. Also, a yarn guide is provided which includes a follower positioned in the groove of the drive roll and a yarn engaging member which extends through the slot of the guide rails and such that the rotation of the drive roll causes the yarn guide to reciprocate back and forth along the slot between the guide rails. A system of this general type is disclosed in U.S. Pat. No. 3,664,596 to Lenk.
The yarn guide as disclosed in the above Lenk patent includes a plate like member positioned between the follower and the yarn engaging member, and the plate like member has a generally diamond shaped outline in plan view, so as to define opposite pairs of parallel guide edges which are designed to alternately engage opposing groove walls on the guide rails as the yarn guide reciprocates. Specifically, one pair of parallel guide edges engages the opposing walls of the guide rails as the guide moves in one direction, and the opposite pair of parallel guide edges engages the opposing walls during movement in the opposite direction. In the reversal areas, wherein the cross spiraled groove reverses its pitch, the yarn guide pivots about an axis which is perpendicular to the drive roll to effect its alternative orientation with respect to the guide rails.
As also disclosed in the above Lenk patent, the guide rails enclose the plate like member of the yarn guide on both the front and rear sides, so that the traversing guide is positively guided both in the axial direction along the slot, as well as in the two directions which are perpendicular to the axis of the cross spiraled drive roll. A traversing yarn guide of the above described type has found widespread use in traversing systems for winding machines processing man-made yarns, and which operate at speeds above 1000 m/min.
As will be apparent, the traversing speed of the yarn guide depends upon the winding speed. In addition, the build of a proper cylindrical package necessitates the very rapid reversal of the yarn guide at the stroke ends. Stated otherwise, the cross spiraled groove of the drive roll should have a very small radius of curvature at the stroke reversal points. As a result, the traversing yarn guide is subjected to very high accelerations at each stroke end, and the service life of the guide is thus limited by the resulting abrasion and fatigue damage.
It is accordingly an object of the present invention to provide a traversing yarn guide of the described type, and which has improved service life.
Prior attempts to improve the service life have involved attempts to minimize the weight of the guide, and the selection of optimum materials. Also, relatively large radii of curvature of the cross spiraled groove have been accepted at the stroke reversal points, which are not totally satisfactory from the viewpoint of winding technology and package build.